GREYMOUTH, New Zealand (Agencies) - Rescuers in New Zealand were testing a high-tech robot Monday that they hope will provide key information in their search for 29 miners trapped underground. A toxic mix of gases inside the coal mine still made it too risky for humans to enter Monday night, officials said. But the robot could enter in the reasonably near future, Pike River Coal CEO Peter Whittall told reporters. No one has heard from the men - ages 17 to 62 - since an explosion inside the mine around 4pm Friday. We still remain optimistic. Were still keeping an open mind, but we are planning for all outcomes. ... Were planning for the possible loss of life as a result of whats occurred underground, said Gary Knowles, superintendent of the Tasman Police District. Whittall said work to drill a small bore hole Monday had been very successful. He said it was 135 meters (443 feet) deep Monday evening - about 15 meters (49 feet) away from its target. Once the six-inch-wide hole breaks through, rescue workers will be able to collect gas samples and other data from a new area of the mine, providing information that could aid in the rescue. Workers also expect to put laser imaging gear down the hole to create a real-time image of what it looks like inside the mine, which is located on New Zealands west coast between Greymouth and Reefton. Sending in the military-operated robot will be a key part of the search process, Knowles said. Sending a robot in to look around is the first step of that, to assess the damage, to see how far we can go, he said. Police on Monday released for the first time the names, ages and nationalities of the 29 men. Most of the missing are from New Zealand, but there are also miners from Australia, Scotland and South Africa in the group. Two of their colleagues escaped the mine soon after the explosion by walking out through a tunnel, the mouth of which is about 2.2 kilometers (1.4 miles) from where the 29 missing men might be. We owe it to the men that are underground, that in undertaking the rescue we do it in a way that doesnt endanger their lives any further, Prime Minister John Key told reporters earlier Monday. Were going to get through this and do everything we possibly can to get the men out alive. As they did during the weekend, those in charge of the mine and rescue operation said tests of air quality inside the mine indicated that conditions were not safe enough to send in rescuers. They have cited elevated carbon monoxide and methane levels. Were still in a hazardous environment. Were still in an atmosphere that is unsafe for men to go into, Whittall said. While drinking water is available inside the mine, the trapped men likely only brought enough food for a single day. The mine is ventilated. Rescuers are holding out hope that the men are breathing fresh air in a ventilation shaft, and they say theyre committed to searching until they find the miners. Were not stopping. We are going forward and we are going forward until we have a result, Knowles said.